Powershift type countershaft transmission for vehicles

0001The invention relates to an interruption in tractive force shiftable countershaft transmission for motor vehicles, as explained in the preamble of claim 1 Art.

0002From DE-A-40 31 851 an interruption in tractive force shiftable countershaft transmission for motor vehicles, the known in the preamble of claim 1 explained type.

0003In this known countershaft transmission is between a flywheel that the input part of a friction clutch forms, a direct driving connection to a first Transmission input shaft is provided and the output of the Friction clutch with a first transmission input shaft comprehensive second transmission input shaft in the form of a Hollow shaft. On the first transmission input shaft here are essentially the fixed gears of the gear stages and arranged on a parallel with the two transmission input shafts, Countershaft are essentially the loose wheels of disposed gear steps, wherein arranged between pairs Idler gears on the countershaft claw or synchronous clutches are arranged around the individual gear stages to turn.

0004On the second transmission input shaft in this case, the fixed gears located the lowest and the highest speed stage and in contrast to the other gear stage is at the second highest Gear, the fixed wheel on the countershaft and the Loose wheel arranged on the first transmission input shaft.

0005Should this known countershaft gear the Motor vehicle to be approached, it must by inserting the Sliding sleeve for 1st gear a driving connection between prepared the loose wheel of the first gear and the countershaft will. Subsequently, by controlled engagement the friction clutch of the starting operation performed. Should now be switched from 1st gear to 2nd gear, so must disengaged at the beginning of the shift, the friction clutch be so that the sliding sleeve that. for the 1st and 5 Passage is provided, adapted from the 1st gear and 5th gear can be inserted. Reference is now again the friction clutch indented controlled, thereby grinding the Friction clutch in connection with the translation. 5 Ganges a speed adjustment to the loading speed for 2nd gear yields. Once the appropriate loading speed is reached, can now by shifting the sliding sleeve for the 2nd gear bumpless loss of traction free Turn into 2nd gear carried.

0006However, the known countershaft gear case has the Disadvantage that by the beginning of the circuit from the first Gear to 2nd gear required disengagement of the friction clutch a short-term interruption of traction occurs, to an undesirable high rotation of the engine can lead.

0007From EP-A-0173117 is an interruption in tractive force shiftable countershaft transmission for motor vehicles, in which a drive motor through a direct connection a first transmission input shaft drives, on which a plurality disposed of fixed gears of gear stages and parallel to a countershaft is disposed on the a plurality of idler wheels for the different grades are arranged, wherein arranged between pairs loose wheels each arranged a claw or synchronous clutch is.

0008With the transmission input shaft, directly to the drive motor is connected, is the input part of a friction clutch rotatably connected, the output part with a second Transmission input shaft is connected in the form of a hollow shaft, on the fixed gear wheels of 5th gear and reverse gear are arranged.

0009A starting process of the motor vehicle is by inserting the sliding sleeve began to 5th gear, wherein first the Friction clutch is disengaged. Hereinafter, now, the Friction clutch controlled, so indented contact type, such that once the loading speed for 1st gear reached is, the sliding sleeve can be inserted smoothly into 1st gear can, and thereafter the friction clutch is disengaged, so that the torque is transferred through the wheel of 1st speed. To engage 2nd gear is again the friction clutch indented by grinding in a controlled manner, so that the insertion speed of the 2nd gear set can, whereupon at this speed is reached the sliding sleeve is shifted to the 2nd gear to the wheel for the second bringing gear to transfer torque. Subsequently is back disengaged friction clutch.

0010The known countershaft transmission has the disadvantage in that, since the starting operation on the gear of the highest Transition, for example, the 5th gear is performed, the friction clutch a considerable friction loss and hatchability must have, which often no longer in power generating applied usual simple toughened friction clutch can be, but a running in oil wet Multi-plate friction clutch has to be used.

0011The object of the invention is to provide a countershaft gear as explained in the preamble of claim 1 to improve art such that, using the simpler Toughened friction coupling a traction nondisruptive Turn all gear stages is made possible, without the critical startup range when changing gears between the 1st and 2nd gear, a torque interruption occurs.

0012According to the invention this object is achieved by a countershaft gear of the preamble of claim 1 type explained that in the characterizing part of claim 1 has identified characteristics.

0013Characterized in that between the input part of the friction clutch and the first transmission input shaft provided for direct Connection is formed as a shiftable jaw clutch and between the output of the friction clutch and the two transmission input shafts, a switchable synchronizer clutch is provided, the drive-controlled on the can Friction clutch and the translation of the 1st gear take place, after which only the direct connection between the input part of the friction clutch and the first transmission input shaft produced by the switchable claw coupling becomes.

0014If now for switching from 1st to 2nd gear, the friction clutch disengaged, there remains a torque path via the switched maintain claw clutch for wheel of 1st gear and there is no disturbing high rotation of the drive machine. The switchable synchronizer clutch, in the compound is connected to the output of the friction clutch, is now brought into engagement with the gear set of the 5th gear and then again the friction clutch is engaged controlled. Once the loading speed of the 2nd gear is reached, the sliding sleeve of the second gear is shifted to the wheel set to make the 2nd gear positively and after disengagement the friction clutch the torque is transferred now exclusively on the wheel of 2nd gear.

0015In the other claims are expedient embodiments the invention will be explained.

0016The invention is illustrated in the drawings accompanying a shown embodiment explained in more detail. It shows:<dl tsize="7"><dt>Fig. 1</dt><dd>a transmission diagram of a countershaft transmission according to the invention in the neutral position;</dd><dt>FIG. 2</dt><dd>the transmission diagram of FIG. 1 in the operating position for a starting, the torque transmission to forming gear parts here are in their respective switching position drawn and the torque curve through increased Strokes represented;</dd><dt>Fig. 3</dt><dd>the transmission diagram of FIG. 1 after completion Starting operation in 1st gear;</dd><dt>Fig. 4</dt><dd>the transmission diagram in the switch position for the preparatory phase of a gear change from 1st gear to 2nd gear;</dd><dt>Fig. 5</dt><dd>the transmission diagram of FIG. 1 during the Synchronization phase for a circuit from. 1 to 2nd gear and</dd><dt>Fig. 6</dt><dd>the transmission diagram of FIG. 1 in its Shift position after a completed circuit from 1st gear to 2nd gear;</dd><dt>Fig. 7</dt><dd>the transmission diagram of FIG. 1 in the preparation phase for a shift from 2nd gear in 1st gear and </dd><dt>Fig. 8</dt><dd>the transmission diagram of Fig. 1 according to the conducted circuit from 2nd gear to 1st Corridor.</dd></dl>

0017The structure of the countershaft transmission of the invention will be explained in connection with FIG. 1, in which the individual provided transmission elements with corresponding reference numerals are that only in the further figures 2-8 Repeat with the difference that in the torque path switched transmission parts in their connected Documents are drawn and the power flow through increased Strokes is indicated.

0018A drive motor 1, preferably a combustion engine with a crankshaft 2 drives a flywheel 3, which in conventional Way connected to a friction disc clutch 4 is which and consisting essentially of an input element 5 an output member 6 is.

0019The countershaft transmission comprises a first transmission input shaft 7 and a second transmission input shaft 8, wherein the second transmission input shaft as a first Input shaft 7 comprehensive hollow shaft is constructed. 8 in the Countershaft gears are gear sets for gears 1 arranged to 5, and preferably the fixed wheels 9, 11, 13 and 15 are arranged on the first gearbox input shaft 7 and their mating gears or idler gears 10, 12, 14 and 16 on one arranged parallel to the transmission input shafts 7 and 8 Countershaft 17 are arranged. The countershaft 17 is connected to a final drive 18th

0020From gear set 19 and 20 of the 5th gear, the fixed wheel 19 arranged on the countershaft 17 and the idler gear 20 fixed is arranged on the second transmission input shaft eighth

0021Between two adjacent loose wheels 10 and 12 or 14 and 16 are in a known manner with corresponding synchronizing clutches Sliding sleeves 21 and 22.

0022In contrast to the known prior art is the direct Connection between the flywheel 3 and the first transmission input shaft 7 is formed as a shiftable claw clutch 23 and output member 6 of the friction clutch 4 is not in direct driving connection with the first transmission input shaft 7, but is this a switchable synchromesh clutch 24 or the on the hollow shaft 8 arranged loose wheel 20 of the 5th gear connectable.

0023The operation of the countershaft transmission of the invention will be described in connection with the figures 2 explained to 8, in which the torque transmission path to the respective forming gear elements through a greater Line thickness are highlighted.

0024From Fig. 2, the starting process can be seen, in which at first nor disengaged friction clutch 4, the synchronizer clutch 24 is displaced such that a driving connection between the output element of the friction clutch 6 and the first transmission input shaft is manufactured. If now by controlled engagement of the friction clutch 4 a torque transmitted, so that torque is transmitted via the synchronous coupling 24 transmitted to the first transmission input shaft 7 and from there via the gear set of the first gear and the in Position for 1st gear synchronizer clutch 21 located on the countershaft assigned to it and the final drive 20 sent.

0025If the starting process is completed, is, as shown in FIG. 3 be seen, the friction clutch 4 is disengaged and in its Place the dog clutch 23 engaged, a direct driving connection between the flywheel 3 and the first Transmission input shaft 7 produces. The additional torque flow remains above the gear set of the first gear and the synchronizer clutch on the countershaft and the final drive.

0026If now, starting from the shift position in Fig. 3 a Circuit from 1st gear to 2nd gear will be prepared so first, the synchronous clutch 24 into engagement with the is brought loose wheel 20 of the 5th gear and thereafter the Friction clutch 4 engaged controlled until the by the Gearset of the 5th gear extending torque flow a Relief of the gearset of the 1st gear causes, thereby this, as can be seen from FIG. 5, in the neutral position and then in the seen in FIG. 6 position can be switched to the 2nd gear. Below this Circuit, the friction clutch 4 is disengaged again and the Drehmomentübertragungsfluß runs over the dog clutch 23 and the gear set of the 2nd gear.

0027If now for example again a downshift from 2nd gear to 1st carried gear, the friction clutch 4 is controlled again engaged, thereby the torque to be before engaged synchronizer clutch 24 on the loose wheel 20 of the 5th Ganges transfers and until again the gearset the 2nd speed torqueless is because with contact Clutch inserted 5th gear, the torque transmission takes over. Therefore, without any problems, a circuit of Synchronous clutch from the position of the 2nd speed in the neutral position and then to the position for 1st gear and is carried by disengaging the friction clutch 4 subsequently again a torque flow via the dog clutch 23 and provided the gear set of the 1st gear.

0028The inventive design of the countershaft transmission the advantage is achieved that the drive-over can take place the gear set of the first gear and simultaneously is ensured by the additional couplings 23 and 24, that during a gear change from 1st gear to 2nd gear and Here, the required disengaging the friction clutch 4 may occur no runaway of the drive motor.

0029Of course, the invention are hereinafter Linking the controlled friction clutch 4 and the transmission input shafts 7 and 8, a wide variety of transmission designs possible but without broadening the scope of the present Invention.

0030For example, the output element of the friction clutch more clutches optionally with the idler gear of the highest Ganges, one with the first transmission input shaft or with any other loose wheel of a gear are connected.

0031The output element of the friction clutch can also further Clutches optionally with any loose wheels or with the first transmission input shaft to be connected.

0032Instead of the simple friction clutch may of course a wet multi-plate or other suitable friction clutches be used.